Comment 6 for bug 1337340

The original issue is a little different to the one linked by elmo (note the different error message, "Closed explicitly" vs. "no reachable servers"). I believe the issue that elmo reports has been fixed (lp:1339240).

The original error is because Mongo has taken >30s to start listening on its socket, probably because it's setting up replica sets which can take a while. The timeout has been increased on trunk and in 1.20.1.